Cleansing cosmetics contain scrubbing agents. The scrubbing agent exfoliates the old stratum corneum by the physical action. As the scrubbing agent, microscopic plastic particles (such as polyethylene particles) have been known (See, for example, Japanese Unexamined Patent Application Publication No. 2001-278778). The plastic particles are lightweight and easily absorb chemical substances such as the pesticide and therefore, it is difficult to remove the plastic particles in the sewage treatment plant. Accordingly, the plastic particles flow into rivers, oceans, ponds, swamps, and the like, and the plastic particles are accumulated in fish and shellfish. Through such fish and shellfish, the plastic particles may have an influence on human bodies.
Japanese Unexamined Patent Application Publication No. 2011-225548 discloses that the scrubbing agent made of particular silica-gel particles provides the user with the favorable exfoliating property. At the same time, since the silica-gel particles collapse when the particles are rubbed on a subject, the stimulation on the subject is reduced.
The silica-gel particle contains water by 50 to 700%. Due to the method of producing the silica-gel particles, it is estimated that the particles have porosity. Therefore, it is concerned that the silica-gel particles might be categorized as the nanomaterial described below. It has not been verified that the particles categorized as the nanomaterial directly lead to the serious problem in environment, health, or safety but users and consumers will demand to avoid using the particles categorized as the nanomaterial.
In the announcement made by the European Commission as of Oct. 18, 2011, the substances or materials which satisfy any of the following (1) and (2) are categorized as the nanomaterial.
(1) the substances or materials containing particles for more than 50% in the number size distribution in the range of 1 to 100 nm
(2) the substances or materials with a specific surface area (SA) per unit volume of more than 60 m2/cm3 (the substances or materials whose specific surface area per unit weight is more than 27 m2/g at a silica gravity of 2.2 g/cm3)
The typical porous silica particles have both the nanometer-size pores and the large specific surface area and therefore correspond to the nanomaterial.
If the definition of the nanomaterial is introduced to REACH in the future, it may be possible that the submission of various kinds of documents for the use of the particles categorized as the nanomaterial is required. Therefore, the time and cost may be required in the procedure and this may interrupt the industrial use.
Japanese Unexamined Patent Application Publication No. 10-226621 discloses the cosmetic containing the collapsible particles. Here, the particle diameter is 100 to 2000 μm, the mean particle diameter of the primary particles is 100 μm or less, and the micro compression strength is 0.002 to 0.1 kgf/mm2. However, since the primary particles contained in the cosmetic are large, the particles themselves have high strength. For this reason, this cosmetic tends to hurt the corneum, gives the very raspy feeling, and so on; thus, the texture characteristics required for the scrubbing agent cannot be obtained easily.